CN101336440A - A method of forming a securitized image - Google Patents

Abstract

There is disclosed a method of forming a securitized image comprising: obtaining a host image which is to be visible to an observer, obtaining a latent image to be concealed within the host image, adjusting the saturation of regions of at least one of the host image and the latent image such that when the latent image and the host image as adjusted are subsequently combined, the saturation of the combined regions will more closely approximate the saturation of corresponding regions of the original host image; and combining the latent image, and host image as adjusted to form a securitized image.

Description

Form the method for securitized image

Technical field

The present invention relates to a kind of method that forms securitized image, also relate to a kind of safety equipment of safe in utilizationization image.In one embodiment, the sub-image behind the coding is hidden in the visible master image.Embodiments of the invention can be applied to provide safety equipment, safety equipment to can be used for identifying file or for example legitimacy and the existence of the certificate of credit card and so on.Other embodiment can be used for providing the novel teachings of resisting forgery.

Background technology

For the primitiveness of the document of identifying and verify for example banknote, credit card and so on and device and prevent to its unauthorized copying of carrying out or modification frequent equipment safe in utilization.Safety equipment are designed to provide the proof of certain evaluation and prevent to duplicate.Although multiple available techniques has been arranged, always need to be applied to provide the further technology of safety equipment.

Multiple technologies have been developed and have been used for sub-image is hidden in security document or device.Such technology the earliest may be watermark.In this method, sub-image is set on the paper substrate, makes to can't see this image when checking paper under the reflective condition, but can see this image under transmissive state.

The method that is used for the hidden image more recently of Secure Application comprises and is called as " scrambling mark (Scrambled Indicia) ", at United States Patent (USP) 3, describe with analog in form in 937,565, in patent WO 97/20298 with the formal description of computerize, digital version.In the latter's technology, computer program burst effectively will be hidden the image that is called in " input picture sheet " parallel rectangular.Then they are produced a series of thinner " output map photos " by scrambling, and " output map photo " be it seems that with human eye disorderly form is incorporated in the image.Yet when checking by the specific installation that comprises many micro-lenslets, original image is rebuilt, thereby presents visible hidden image.

This scrambling image can be incorporated in the visible background picture by the thickness of adjusting the feature in the scrambling image.

Patent WO 97/20298 also described the scrambling image how by the computerized algorithm sequencing be incorporated into visible picture.Original image is digitized, and is separated into cyan, magenta, yellow and black component.Then, one or more scrambling images are incorporated into the separating part of cyan and magenta.They are used to substitute initial protion, and print as usual.

Multiple patent also described by " modulation " be used for the line of printing image-or dot pattern hide sub-image.For printing image, the printer of specialty uses the technology of various being called as " screen (screening) ".Comprising round screen, random screen, line screen and oval screen.The example of such screen is referring to United States Patent (USP) 6,104,812.In fact, picture is split into a series of images element, and typically, pictorial element is point or the line and the combination thereof of different shape.These Points And lines are minimum usually, can be observed much smaller than human eye.Therefore, the image that uses such screen to print has continuous color harmony concentration at human eye.

Can be by seeming similar line and some screen each other and put and create hidden image with two.The position, shape or the direction that are used to print the line element of screen by change come the processing procedure of hidden image formally to be called " line modulation ".The processing procedure that the point of printer screen is deformed or moves with sub-image is called as " some modulation ".

The theory of line and some modulation is described (Issac Amidror, " The Theory ofthe Moir é Phenomenon ", Kluwer Academic Publishers, Dordrecht, 2000, pages 185-187) by Amidror.When two local period structures with same period superposeed each other, the image of generation had shown that two periodic structures the microstructure in zone of the differential seat angle of α=0 ° may be changed (and not the Moir é pattern of generation rule).The degree of the change of microstructure can be used to produce sub-image, and this sub-image is only just high-visible to the observer when local periodic structure is correlated with stack.Therefore, only when being applied non-modulation structure with correspondence, sub-image just can be observed.Correspondingly, modulation image can be incorporated into original document and corresponding to the decoding screen of non-modulation structure, the decoding screen be used for by for example on modulation image overlapping non-modulation decoding screen check to present sub-image whether document is original.

The example of using the line modulation to hide sub-image is described in following a plurality of patent: US6,104,812, US 5,374,976, CA 1,066, and 109, CA 1,172,282, WO03/013870-A2, US 4,143,967, WO 91/11331 and WO2004/110773 A1.A kind of technology or its microcosmic peer to peer technology " μ-SAM " that is called as screen angle modulation " SAM " is described in detail in U.S. Patent number 5,374,976 and Sybrand Spannenberg book " Optical Document Security; Second Edition " (editor: Rudolph L.vanRenesse, Artech House, London, 1998, page169-199) the 8th chapter in all is incorporated herein by reference.In present technique, in the pattern of the micro short line segment that is provided with in the cycle, by with continuously or the mode of blocking modulate micro short line segment angle relative to each other and create sub-image.When checking with naked eyes, pattern show as uniform in the middle of color or gray scale, superimposed during when it with the identical non-modulation pattern on the transparent substrates, can observe sub-image.

The example of using the some modulation to hide sub-image is described in the various patents, comprises WO02/23481-A1.

In order to overcome sub-image frequent apparent restriction under optics amplifies of using scrambling, line or some modulation to imply, in the recent period we developed handle minimum that printer can use may pictorial element (pixel) with the technology of the printing screen of creating brand-new type.Such technology can be described to " shadow tone " hidden image.Known have two kinds of processing printer pixels at least to create the method for shadow tone hidden image.These methods are called " modulation digital image " (MDI) widely.The example of such processing procedure is described in WO2005002880-A1 and WO2004109599-A1, and described equipment is called PhaseGram and BinaGram.

In PhaseGram, a plurality of images as photograph and so on are digitized and then are separated into various gray scales or tone saturation degree.Then, the line screen with various displacements is coated over the black region of each separating part, and the line screen is replaced according to the gray scale or the tone saturation degree of separating part.Adjusted image then is combined, to create new printing screen.All these is finished in the digital processing process by computerized algorithm.Use the digital machine method to allow the structure and the final performance of the various hidden images that in the processing of using comparable simulation (photograph), can not reach.New printing screen is extremely complicated, even under the situation of amplifying fully, human eye can not be observed hidden image.

Notion and the PhaseGram of BinaGram are similar, comprise that the algorithm that uses a computer produces new printing screen.Yet in this case, employed ultimate principle is not a displacement line screen, but compensation principle, wherein the new element of each element of hidden image and complementary concentration is paired.

Use the described technology that is called TonaGram of WO2005/069198-A1, such equipment can be incorporated into visual image.TonaGram comprises the technology of the tone value that is used to handle one or more sub-images and master image, by hiding sub-image for sub-image assigned hue scope.In this manner, sub-image as BinaGram, PhaseGram or other hidden images, can be hidden in the visible master image.

It will be favourable that another technology of hiding one or more images in visual picture is provided.

Summary of the invention

In an embodiment, the invention provides a kind of method that forms securitized image, described method comprises:

A) obtain the visible master image of observer;

B) acquisition will be hidden the sub-image into master image;

C) adjust the saturation degree in the zone of at least one in master image and the sub-image, make that the saturation degree of combination zone more approaches the saturation degree of the corresponding region of original master image when adjusted sub-image and master image make up subsequently; And

D) adjusted sub-image and master image are made up, form securitized image.

In an embodiment, the present invention includes the adjustment saturation degree, so that minimize the difference of the saturation degree of the saturation degree of the image that is combined into by sub-image and adjusted master image and original master image.

In an embodiment, the present invention includes the saturation degree of adjusting the zone at least one master image and the sub-image, comprising:

Each master image and sub-image are separated into the digitizing gray scale of each image of complete definition when making up or the set of color saturation;

To each gray scale or color saturation, use matching algorithm, the gray scale of the pictorial element in the sub-image or the same grayscale of color character and master image or the correspondence image element of color saturation are mated.

In an embodiment, the present invention includes combination adjust the back sub-image and master image, comprising:

According to the visual properties of the correspondence image element of selected sub-image, the selected pictorial element of each gray scale or color saturation in the master image is changed, to form the separating part of revision; And

Thereby the separating part of combination revision is created securitized image.

In an embodiment, the present invention includes the acquisition sub-image, comprise the sub-image of selecting one or more image and the formation that will imply into master image to comprise one or more images.

In an embodiment, the present invention includes:

A) obtain another sub-image that to hide at least;

B) saturation degree in the zone of at least one in adjustment securitized image and another sub-image, make that the saturation degree of combination zone will more approach the saturation degree of the corresponding region of original securitized image when adjusted another sub-image and securitized image make up subsequently; And

C) adjusted another sub-image and securitized image are made up, form another securitized image.

In an embodiment, the present invention includes sub-image is the hidden image of coding, and the hidden image of described coding can use the decoding screen to decode.

In an embodiment, the technology that the present invention includes by selecting from following group forms sub-image: scrambling mark, line or some modulation, PhaseGram and BinaGram.

In an embodiment, sub-image is the digital modulation image.

In an embodiment, the present invention includes a plurality of sub-images can be hidden into visible securitized image by the mode of different decoder decodes separately.

The present invention also extends to the safety equipment of the securitized image that use makes according to said method.

Such safety equipment can be the parts that autonomous device (for example being printed on the substrate) maybe can be combined into document, file etc., for example, can be used to passport, safety card, credit card and banknote.

Therefore, the invention provides a kind of safety equipment, comprise securitized image, wherein, sub-image is hidden in the master image by following method: the saturation degree of adjusting the zone of at least one in master image and the sub-image, make that the saturation degree of combination zone more approaches the saturation degree of the corresponding region of original master image, and sub-image and adjusted master image are combined to form securitized image when adjusted sub-image and master image make up subsequently.

In an embodiment, the present invention includes sub-image is the hidden image of coding, and the hidden image of described coding can use the decoding screen to decode.

In an embodiment, sub-image is the digital modulation image.

In an embodiment, the present invention includes a plurality of sub-images is hidden into visible securitized image by the mode of different decoder decodes with each.

One skilled in the art will recognize that method of the present invention can typically embed in the program code of implementing said method (or making the user carry out step as selecting and so on), the present invention expands to such program code.Such program code typically embeds in the storage medium.

Correspondingly, the invention provides computer program code, can be carried out by computing machine, make the method for computer-implemented formation securitized image, described method comprises:

A) obtain the visible master image of observer;

B) acquisition will be hidden the sub-image into master image;

C) adjust the saturation degree in the zone of at least one in master image and the sub-image, make that the saturation degree of combination zone more approaches the saturation degree of the corresponding region of original master image when adjusted sub-image and master image make up subsequently; And

D) adjusted sub-image and master image are made up, form securitized image.

Term " securitized image " is used in reference to the image that comprises one or more hidden images.Can recognize that hidden image is so long as the part in securitized image zone.Owing to handle color or gray tone with sub-image, such securitized image is called as " total color management " or " TCM " equipment herein.

In instructions, " pictorial element " refers to the image section that focuses on.Typically, this is the minimum image element (for example pixel of printer or display device) that display or selected technique of display can be used, yet they can be minimum usable image element set (for example 2 * 2 picture element matrixs), depend on required resolution and reproducing technology.

Herein, term " main visual properties " is used in reference to the possible visual properties set that pictorial element can have after digitizing.Main visual properties will depend on the characteristic of original image, and for coloured image, main visual properties will depend on employed color-separated technology.

For gray level image, main visual properties typically depends on black and white.

For coloured image, typically, can use color-separated technology as RGB or CYMK and so on.For RGB, main visual properties is red, green and blue, and each all has maximum saturation.For CYMK, main visual properties is cyan, yellow, magenta and black, and each has maximum saturation.

Typically, after conversion, the visual properties value is relevant with the concentration of pictorial element.That is to say that when original image is a gray level image, visual properties is a gray-scale value, when original image is a coloured image, visual properties is the intensity value of the tone of pictorial element.

Medium tone has been transmitted in concentration that complementary visual properties is grey or tone and the combination of original visual properties.For the gray scale element, medium tone is grey.For the coloured image element, complementary hue is as follows:

Tone Complementary hue

The cyan redness

The magenta green

Yellow blue

Black white

Red cyan

Green magenta

Blue yellow

Typically, the pictorial element in master image or the hidden image is a rectangular array.Yet pictorial element can be set to other shapes.

By following description to the embodiment of the invention, further feature of the present invention will become apparent.

Description of drawings

Below describe the preferred embodiments of the present invention with reference to the accompanying drawings:

Fig. 1 shows the process flow diagram that how monochromatic sub-image is hidden in the example in the colored master image according to first preferred embodiment;

Fig. 2 shows and is used to revise the process flow diagram of master image with the example of the algorithm that comprises hiding sub-image according to first preferred embodiment;

Fig. 3 is the graphic rendition that is used for the algorithm of first preferred embodiment;

Fig. 4 A and 4B show sub-image and how master image is separated into the process flow diagram that constitutes the color-separated part;

Fig. 5 shows the process flow diagram how colored sub-image typically is converted into the formation CYMK separating part of colored PhaseGra;

The separating part that Fig. 6 A to 6D shows CYMK sub-image " original " cyan, magenta, yellow and black is the complementary colors of the negative film by considering other separating parts how, typically is converted into the process flow diagram of the separating part of " revision " cyan, magenta, yellow and black;

How the separating part that Fig. 7 A to 7D shows master image is converted into the process flow diagram of the separating part of creating final securitized image thus according to the separating part of " revision " sub-image of correspondence; And

Fig. 8 is the block diagram of the computing system of preferred embodiment.

Embodiment

Preferred embodiment provides the technology that is used to form securitized image.Sub-image is hidden within the visible master image of human viewer.Create securitized image by the following method: the saturation degree of adjusting the zone of at least one master image in the sub-image, make that the saturation degree of combination zone more approaches the saturation degree of the corresponding region of original master image when sub-image and adjusted master image make up subsequently.

One skilled in the art will recognize that or by implementation step or by requiring the user to the system input information as selection of master image or sub-image and so on, computer program code can be used to implement the technology of the following stated.Such program code can provide on disk or offer the user with other as the mode of downloading by the Internet.

Preferred embodiment 1:

Present embodiment is suitable for most, be black and white (gray scale) or colour but be not limited to master image, but sub-image only is the situation of black and white.

In gray level image, the image that original image is made up of the pel array with different shades of gray typically.Each shades of gray is corresponding to different black (or its complementary colors white) intensity.Yet image may be a coloured image, and this coloured image forms gray level image through additional image processing step, to create gradation effect in final securitized image.

In coloured image, the picture that original image is made up of the pel array with different tones typically, each pixel has the saturation degree that is associated corresponding to tone (or its complementary hue) intensity.

Dominant hue is the color that can separate from original image by the whole bag of tricks well known by persons skilled in the art.The combination of the dominant hue of dominant hue and other different saturations (intensity) provides the wider color perception more required than description object image.Can be used for providing the example of the scheme of dominant hue is redness, green and the blueness of rgb color scheme and cyan, magenta, yellow and the black in the CYMK color scheme.Two kinds of color schemes also can use simultaneously.Also can use other color spaces or picture tone is separated into the separating part of the mass-tone with corresponding complementary look of any amount.

In black white image, has only a tone: black (its corresponding complementary tone is for white).So, black white image can be considered to special coloured image.

Saturation degree is the strength grade that the particular dominant color in each pixel of original image is transferred.Colourless is available minimum saturation degree; The highest saturation degree is corresponding to the maximum intensity that can reproduce dominant hue at this place.

Anyly be used to show that the digital display circuit of continuous-tone image must be reduced to discrete value with weight grade quantity.This all is suitable for gray scale and coloured image.According to a standard (8 bit), the weight scope that is adopted is 256, to 255, is defined as the bright level of graphoscope output from 0 numbering.Therefore, in gray scale is represented, the 255th, white, the 0th, black (promptly each of red, green and blue being had 8 bits).Use RGB (RGB) color system, (255R, 255G are white 255B), and (0R, 0G 0B) are black.Other standards use 65,536 tones (at least at grey; 16 bit standard) and 4096 tones (12 bit standard).Similarly standard can be used for other color-separated technology as CYMK and so on.

Therefore, saturation degree can be represented as mark (promptly colourless=0, maximum tone=1) or other standard values (for example value between 0 (maximum saturation) and 255 (colourless) in 256 color schemes) of using of percentage (promptly colourless=0%, maximum tone=100%) or those skilled in the art.

Dominant hue (N in the image _H) and the quantity of complementary colors and mixed shades typically depend on the medium that is used to produce image.In RGB and CYMK master color scheme, complementary hue is as follows:

The tone complementary hue

A.CYMK cyan redness (by magenta and yellow the composition)

Magenta green (by cyan and yellow the composition)

Yellow blue (forming) by cyan and magenta

Black is white

White black is (in printing at least by cyan, magenta

Look and yellow composition the)

The tone complementary hue

The red cyan of B.RGB (forming) by green and blue

Green magenta (forming) by red and blue

Blue yellow (forming) by red and green

Traditionally, white is as no color pixel.

Mixed shades is as follows:

The tone mixed shades

A.CYMK cyan+magenta blueness

Magenta+yellow is red

Cyan+yellow is green

Random colour+black black

This look of random colour+in vain

Random colour+himself this look

The tone mixed shades

B.RGB red+blue magenta

Blueness+green magenta

The red+green yellow

Random colour+himself this look

Also can use other color spaces well known in the prior art maybe will have the tone separating part of corresponding complementary tone.

In a preferred embodiment, after selecting master image, following following steps:

The sign sub-image to hide into the zone of master image.This zone can be whole master image or be the part of master image.Adjust (using the known method of prior art) and will hide, make it have the size consistent, use aforesaid numeral or analogue technique to be combined into single " hiding " image more than an image sets with this zone into this regional image.Preferably, employing is as the modulation digital image technique of gray scale BinaGram, PhaseGram and so on.

The processing procedure that produces PhaseGram or BinaGram is seen the description of WO2005002880-A1 and WO2004109599-A1.

In PhaseGram, a plurality of images as photograph and so on are digitized and then are separated into various gray scales or tone saturation degree.Then, the line screen with various displacements is coated over the black region of each separating part, and the line screen is replaced according to the gray scale or the tone saturation degree of separating part.Adjusted image then is combined, to create new printing screen.All these is finished in the digital processing process by computerized algorithm.Use the digital machine method to allow the structure and the final performance of the various hidden images that in the processing of using comparable simulation (photograph), can not reach.New printing screen is extremely complicated, even under the situation of amplifying fully, human eye can not be observed hidden image.

Notion and the PhaseGram of BinaGram are similar, comprise that the algorithm that uses a computer produces new printing screen.Yet in this case, employed ultimate principle is not a displacement line screen, but compensation principle, wherein the new element of each element of hidden image and complementary concentration is paired.

2. present, if image is not digitized, each master image and sub-image are digitized as the equivalent canonical array (or matrix) of pixel by using the known method of prior art.That is to say that master image and sub-image are converted into set of pixels.For master image, these pixels can comprise one or more color harmony saturation degrees.For sub-image, present embodiment requires it to be made up of black (be maximum gray scale saturation degree, for example 0) or colourless (be the minimal gray saturation degree, for example 255).One skilled in the art will recognize that for some digital technology that is adopted sub-image should be a gray scale numeral sub-image as gray scale PhaseGram or BinaGram and so on.In this case, do not need this step.Yet other hidden methods may not produce such digitizing.In these cases, dither technique, as order shake or error diffusion dither (as Floyd-Steinberg, Burkes or Stucki process, or the like), can be used to guarantee that all pixels in the sub-image all are maximum (black) or minimum (colourless) gray scale saturation degree.

3. then, master image is separated into its formation color-separated part.These color-separated part typically with can be printed machine or be used to show that the color-separated that equipment presented of final securitized image partly is complementary.So, this step can be limited to single separating part (black and white is presented) or a plurality of separating part four separating parts of CYMK color scheme (for example for).If the combination results of separating part is close to accurate original image, unconventional separation also is possible.These separating parts are called as " original separating part ".

4. present, in each separating part of sub-image and master image, according to position and the position in sub-image picture element matrix [p * q] of pixel in pixel [i * j] matrix of master image, give each pixel distribute unique address (i, j) or (p, q).(if image is not rectangular array, then locations of pixels can define with respect to arbitrary origin, preferably, initial point for coordinate i and j or p and q all provide on the occasion of).In the master image sub-image to hide into the zone must comprise the matrix of p * q pixel.That is to say that it must have with the identical size of sub-image and comprise the pixel identical with the pixel that exists in the sub-image arranges.

5. in each separating part of sub-image and master image, each pixel further is expressed as belongs to master image (H _Ij) or sub-image (L _Pq).

6. in each separating part of sub-image and master image, each pixel has been assigned with descriptor h, and the indication pixel is one of black (or white) or selected dominant hue, wherein h=1 (tone 1) or 2 (tones 2) ... NH (tone NH, wherein NH=integer).Each pixel is assigned to H now _Ij ^hOr L _Pq ^h

7. present, in each separating part of sub-image and master image, define the tone saturation degree s of each pixel, pixel is represented as H _Ij ^h(s) or L _Pq ^h(s), wherein, available saturation gradation quantity is w, and s is the integer between 0 (maximum saturation grade) and the w (minimum saturation gradation), perhaps comprises 0 and w.

8. present, in each separating part of master image, use matching algorithm, wherein,, the p * q matrix of pixel in the master image is changed according to the comparable visual properties of the p in the sub-image * q matrix to each value h.Depend on specified conditions and the sub-image that is adopted, can adopt multiple matching algorithm.Generally speaking, the target of matching algorithm is:

-total saturation degree of abideing by the master image in the minimum Probability Area of image keeps as far as possible the restriction near constant, and (saturation degree=w) zone moves to black (saturation degree=0) zone of corresponding sub-image from corresponding sub-image colourless with the intensity in the master image (tone saturation degree).

Therefore, when using all by unsaturated (colourless; During sub-image that the saturation degree=w) or the pixel of maximum saturation (saturation degree=0) are formed, the preferred embodiment of matching algorithm is as follows:

To each value h, by at L _Pq ^h(s) average all value s in, the average staturation M of calculating sub-image.Then M must be positioned between w (minimum saturation gradation) and 0 (the maximum saturation grade).

Now, each pixel H _Pq ^h(s) change according to following:

● work as L _Pq ^h(s) have saturation degree s=w, and H _Pq ^h(s) saturation degree s＜M:

-H then _Pq ^h(s) be converted to H _Pq ^h(s '), s '=(w*s)/M wherein, $s=H_{\mathrm{pq}}^h\left(s\right)$ Initial saturation.This equation has reflected that the intensity that need reduce pixel in the master image is with the combination with hidden image.The derivation of this equation is as described in the example 1.

● work as L _Pq ^h(s) have saturation degree s=w, and H _Pq ^h(s) saturation degree s 〉=M:

-H then _Pq ^h(s) be converted to H _Pq ^h(s '), wherein s '=w.This equation has reflected that needs increase the intensity of pixel in the master image with the combination with hidden image.The derivation of this equation is as described in the example 1.

● work as L _Pq ^h(s) have saturation degree s=0, and H _Pq ^h(s) saturation degree s＜M:

-H then _Pq ^h(s) be converted to H _Pq ^h(s '), wherein s '=0.This equation has reflected that the intensity that need reduce pixel in the master image is with the combination with hidden image.The derivation of this equation is as described in the example 1.

● work as L _Pq ^h(s) have saturation degree s=0, and H _Pq ^h(s) saturation degree s 〉=M:

-H then _Pq ^h(s) be converted to H _Pq ^h(s '), wherein s '={ (w* (s-M)/(w-M)) }.This equation has reflected that needs increase the intensity of pixel in the master image with the combination with hidden image.The derivation of this equation is as described in the example 1.

Now, the separating part of the master image of generation comprises the pixel in the p * q matrix that has been converted.Therefore, separating part is called as " separating part of revision ".

Should be understood that various algorithm can be used for realizing sub-image hiding in master image.For example, above-mentioned algorithm can be adjusted to the some gain of considering to print in the securitized image process.The texture of other colors as ink transparency, raw material (paper), raw material, point are overlapping or the like, all may influence the algorithm that is adopted.Optionally, can rule of thumb revise or change above-mentioned equation, to realize suitable hiding.One skilled in the art will recognize that the suboptimum technology can provide enough hiding, wherein, the saturation degree of the part of adjustment master image and/or sub-image is closer to be similar to the saturation degree of original master image.In order to obtain best result, the pixel of sub-image should be carried out optimum matching with the pixel of corresponding master image, do not hide sub-image in the master image thereby be implemented in not discernablely.

9. present, use the known method of prior art, the separating part of revising is combined as single image.For example, each separating part may will be monochrome, then form and separate printed board; When each plate was printed to its corresponding color, printed board overlapped each other, and produced last single image.Optionally, the separating part of revision is combination with one another directly, does not need the further for example processing in the display device of graphoscope or other types.

New single image is called as " safe " image, and it comprises sub-image and reaches the formation hidden image that is not hidden in wherein not discernablely.Suitable decoding processing by to securitized image can show hidden image.

Preferred embodiment 2:

The difference of this preferred embodiment and aforesaid embodiment has been to consider the complementary colors of the dominant hue in the sub-image, thereby allows accurately the presenting of colored hidden image in colored master image.Yet present embodiment is suitable for this application, but its purposes is not limited to application therewith.

Embodiment 2 comprises the following step:

1. the sign sub-image will be hidden the zone into master image.This zone can be whole master image or be the part of master image.Adjust (using the known method of prior art) and will imply, make it have the size consistent with this zone into this regional image.Then, also use aforesaid as BinaGram, PhaseGram and so on numeral or analogue technique will imply image sets into this district be combined into single " diving " as.This preferred embodiment promptly comprises the sub-image of the pictorial element with different dominant hues including, but not limited to using colored sub-image.

2. then, master image and sub-image are separated into its formation color-separated part.These color-separated part typically with can be printed machine or be used to show that the color-separated that equipment presented of final securitized image partly is complementary.So, this step can be limited to single separating part (black is presented in vain) or a plurality of separating part four separating parts of CYMK color scheme (for example for).If the quite accurate original image of the combination results of separating part, unconventional separation also is possible.Under all these situations, these separating parts are called as " original separating part ".

3. if image is not digitized, now, each master image and sub-image are digitized as the equivalent canonical array (or matrix) of pixel by using the known method of prior art.That is to say that master image and sub-image are converted into set of pixels.These pixels can comprise one or more color harmony saturation degrees.One skilled in the art will recognize that for some digital technology as gray scale PhaseGram or BinaGram and so on that is adopted, the colourful digital sub-image exists.In this case, do not need this step.Yet other hidden methods may not produce such digitizing.In these cases, dither technique as order shake or error diffusion dither (as Floyd-Steinberg, Burkes or Stucki process, or the like), can be used to guarantee all suitable tone and the corresponding saturation degree thereof of all pixels in the sub-image.

It should be noted that and before carrying out color-separated, to carry out digitizing and coding, and additive method must carry out color-separated before digitizing some method of creating sub-image.Therefore, step 2 and 3 can be implemented simultaneously or implement with the order that is different from said sequence.

Use as the technology of PhaseGram or BinaGram and so on, hide hidden image and hidden image is separated into it and constitute color-separated method for optimizing partly and comprise following process:

(a) hidden image with analog or digital is separated into its formation color,

(b) each color-separated is partial digitized for comprising the gray level image of weight quantity of pre-selected.

(c) use said method that each color-separated partly is converted to its PhaseGram or BinaGram separately.

(d) adjustment is by the strength range of the PhaseGram of the color-separated of above-mentioned (c) generation, the strength range of the digital picture described in above-mentioned to mate (b).

(e) image of Chan Shenging is converted back to its original dominant hue, the color-separated part that provide digitized, comprises hidden image.

(f) when having hidden a plurality of image, use the known method of prior art, all separating parts with same hue are combined as single color-separated part.If the color-separated that produces partly is combined into single image, then produced sub-image.When using suitable method decoding, the image in the sub-image will be represented with color mode.

4. present, in each separating part of sub-image and master image, according to position and the position in sub-image picture element matrix [p * q] of pixel in the picture element matrix [i * j] of master image, give each pixel distribute unique address (i, j) or (p, q).(if image is not rectangular array, then locations of pixels can define with respect to arbitrary origin, preferably, initial point for coordinate i and j or p and q all provide on the occasion of).In the master image sub-image to hide into the zone must comprise the matrix of p * q pixel.That is to say that it must have with the identical size of sub-image and comprise the pixel identical with the pixel that exists in the sub-image arranges.

5. in each separating part of sub-image and master image, each pixel further is expressed as belongs to master image (H _Ij) or sub-image (L _Pq).

6. in each separating part of sub-image and master image, each pixel has been assigned with descriptor h, and the indication pixel is one of black (or white) or selected dominant hue, wherein h=1 (tone 1) or 2 (tones 2) ... NH (tone NH, wherein NH=integer).Each pixel is assigned to H now _Ij ^hOr L _Pq ^h

7. present, in each separating part of sub-image and master image, define the tone saturation degree s of each pixel, pixel is represented as H _Ij ^h(s) or L _Pq ^h(s), wherein, available saturation gradation quantity is w, and s is the integer between 0 (maximum saturation grade) and the w (minimum saturation gradation), perhaps comprises 0 and w.

8. present, use the known method of prior art, each separating part of sub-image is converted to its negative film.In this processing procedure, the dominant hue of each pixel will be converted into its complementary hue.Complementary colors is represented as h=-1 (complementary hue of tone 1) ,-2 (complementary hues of tone 2) ...-NH (complementary hue of tone NH).Therefore, the processing that the sub-image that separates is converted to its complementary hue will cause pixel L _Pq ^h(s) usually become L _Pq ^-h(s).And, because each complementary hue is made of L the mixing of original dominant hue _Pq ^-h(s) can be represented as L _Pq ^{H '+h "}(s), wherein tone h '+h " has provided tone-h.Pixel L _Pq ^{H '+h "}(s) further be represented as L _Pq ^h' (s)+L _Pq ^h" (s).

For example, cyan pixel (being h=1) will become red pixel (h=-1) when being converted into its negative film.Yet redness is made up of magenta (being h=2) and yellow (being h=3).Therefore, produce pixel (L _Pq ¹(s)) negative film has used two other dominant hues (L _Pq ²⁺³(s)) combination.This is represented as L now _Pq ²(s)+L _Pq ³(s).

9. present, the pixel and the negative film thereof that comprise identical dominant hue in the original separating part of each of sub-image are combined into single separating part.Therefore, the original separating part L of each of sub-image _Pq ^h(s) added other separating parts (L that is colored as sub-image accordingly now _Pq ^{H '+h "}The pixel of negative film (s)).That is to say, for the original separating part of the tone h in the corresponding sub-image, each pixel L _Pq ^h(s), if h '=h then adds L _Pq ^h' (s), or as if h "=h then adds L _Pq ^h" (s).The separating part that produces is represented as L _Pq ^h (s) and be called as " the sub-image separating part of revision ".

10. present, shake each sub-image separating part, make the saturation degree of pixel become unsaturated (colourless; Saturation degree=w) or maximum saturation (saturation degree=0).That is to say L _Pq ^h (s) be converted into L _Pq ^h (s=0) or L _Pq ^h (s=w).This can pass through dither technique, realizes as order shake or error diffusion dither (as Floyd-Steinberg, Burkes or Stucki process, or the like).

11. now, in each separating part of sub-image and master image, use matching algorithm, wherein, the p * q matrix of pixel in the master image is changed according to the comparable visual properties of the p in the sub-image * q matrix at each value h.Depend on specified conditions and the sub-image that is adopted, can adopt multiple matching algorithm.Generally speaking, the target of matching algorithm is:

-keep the intensity in the master image (tone saturation degree) being moved to black (saturation degree=maximum) zone of corresponding sub-image from colourless (saturation degree=0) zone of corresponding sub-image in accordance with total saturation degree of the master image in the littler zone of image as far as possible near the restriction of constant.

Therefore, the preferred embodiment of matching algorithm is as follows:

To each the value h, by

In average all value s, calculate the average staturation M of sub-image, wherein s can be that original s (as finding in the step 8) or s are restricted to 0 or w (as finishing in the step 9).Then M must be positioned between 0 (minimum saturation gradation) and the w (maximum saturation grade).

Now, each pixel H _Pq ^h(s) change according to following:

● work as L _Pq ^h(s=0 or w) has saturation degree s=w, and H _Pq ^h(s) saturation degree s＜M:

-H then _Pq ^h(s) be converted to H _Pq ^h(s '), s '=(w*s)/M wherein, wherein $s=H_{\mathrm{pq}}^h\left(s\right)$ Initial saturation.This equation has reflected that the intensity that need reduce pixel in the master image is with the combination with hidden image.The derivation of this equation is as described in the example 1.

● work as L _Pq ^h(s=0 or w) has saturation degree s=w, and H _Pq ^h(s) saturation degree s 〉=M:

-H then _Pq ^h(s) be converted to H _Pq ^h(s '), wherein s '=w.This equation has reflected that needs increase the intensity of pixel in the master image with the combination with hidden image.The derivation of this equation is as described in the example 1.

● work as L _Pq ^h(s=0 or w) has saturation degree s=0, and H _Pq ^h(s) saturation degree s＜M:

-H then _Pq ^h(s) be converted to H _Pq ^h(s '), wherein s '=0.This equation has reflected that the intensity that need reduce pixel in the master image is with the combination with hidden image.The derivation of this equation is as described in the example 1.

● work as L _Pq ^h(s=0 or w) has saturation degree s=0, and H _Pq ^h(s) saturation degree s 〉=M:

-H then _Pq ^h(s) be converted to H _Pq ^h(s '), wherein s '={ (w* (s-M)/(w-M)) }.This equation has reflected that needs increase the intensity of pixel in the master image with the combination with hidden image.The derivation of this equation is as described in the example 1.

Now, the separating part of the master image of generation comprises the pixel in the p * q matrix that has been converted.Therefore, separating part is called as " separating part of revision ".

Should be understood that various algorithm can be used for realizing sub-image hiding in master image.For example, above-mentioned algorithm can be adjusted to the some gain of considering to print in the securitized image process.The texture of other colors as ink transparency, raw material (paper), raw material, point are overlapping or the like, all may influence the algorithm that is adopted.Optionally, can rule of thumb revise or change above-mentioned equation, to realize suitable hiding.One skilled in the art will recognize that the suboptimum technology can provide enough hiding, wherein, the saturation degree of the part of adjustment master image and/or sub-image is closer to be similar to the saturation degree of original master image.In order to obtain best result, the pixel of sub-image should be carried out optimum matching with the pixel of corresponding master image, do not hide sub-image in the master image thereby be implemented in not discernablely.

12. now, use the known method of prior art, the separating part of revising is combined as single image.For example, each separating part may be reduced to monochrome, then forms and separates printed board; When each plate was printed to its corresponding color, printed board overlapped each other, and produced last single image.Optionally, the separating part of revision is combination with one another directly, does not need the further for example processing in the display device of graphoscope or other types.

New single image is called as " safe " image, and it comprises sub-image and reaches the formation hidden image that is not hidden in wherein not discernablely.Suitable decoding processing by to securitized image can disclose hidden image.

Fig. 8 shows the computing system of preferred embodiment.Computing system comprises importation 802, image processing section 835 and output 880.Importation 802 is set to allow the user to import hidden image to be processed subsequently and master image.Hidden image selector switch 805 allows the user to browse the image that will imply with access in computer file system.Typically, the 808 retrieval hidden images (or more than a hidden image) from the hide image data storehouse.In case the user uses hidden image selector switch 805 to select hidden image, this hidden image just is provided for sub-image and forms device 810.Sub-image forms device can form sub-image automatically by use the algorithm that sub-image algorithm or user select from sub-image algorithm data-base 815.

The master image that is obtained can be for example relevant with the I.D. that will produce people's a picture.Correspondingly, system comprises the master image catcher 825 that is connected with system as digital camera and so on, and the master image that is used to select to be caught is used for the further master image selector switch 820 of processing.Those skilled in the art also can recognize, can use file system to retrieve master image.

System also combines workspace selector switch 830, allow the user select sub-image will in conjunction with as in the master image where.The subregion of image for example.Those skilled in the art also can recognize, can in workspace selector switch 830, realize locating automatically sub-image rule.

After the workspace was selected, master image was provided for image processing section 835 with data that defined the workspace and sub-image.Image processing section comprises that saturation degree separation vessel 840, gray scale/match colors device 850, revision separating part form device 860 and revision separating part combiner 870.In case 870 pairs of revisions of revision separating part combiner separating part makes up, just formed securitized image and securitized image has been offered securitized image output 880.Typically, securitized image output will be the form of printer, be used to print securitized image.

Example 1 (monochromatic sub-image is in the full color master image):

With reference to Fig. 1: master image is made up of the full color picture that is designated as 1.Typically, master image 1 adopts the user input of present technique with the computing machine of the program code that tells on by having carried out.For example, by selecting to be stored in the master image in the computing machine.The image 2 that will lie in the master image is monochromatic (black and white).Master image is separated into it and constitutes dominant hue.In this example, adopt the CYMK separable programming, master image be separated into:

-magenta (M) separating part, 3

-yellow (Y) separating part, 4

-black (K) separating part, 5

-cyan (C) separating part, 6

Typically, hidden image 2 is imported in the mode identical with master image by the user.Hidden image is converted into sub-image 7, for example uses the PhaseGram technology in this example.The area identification that sub-image will be hidden into master image is 1a.Zone 1a has the pixel with sub-image 7 equal numbers and arrangement.To each separating part, this zone and sub-image 7 compare.In Fig. 1, the zone of the cyan separating part that sub-image will be hidden is shown 6a.Zone 6a is by overlapping 100 comparing it with sub-image 7, and uses algorithm, makes the zone of the master image part under the sub-image white pixel more shallow 12, the zone under the sub-image black picture element darker 13.Fig. 2 describes this algorithm in detail.

Each pixel H in the 6a part _PqHave the cyan dominant hue, saturation degree is s, and s is (the minimum saturation degree of w=wherein between 0≤s≤w; The 0=maximum saturation).Sub-image L _PqIn the average staturation of mean pixel be M.

This method is included in step 200 and determines for L _Pq, s=0 or w.If for L _Pq, s=0, then respective pixel H _PqSaturation degree be adjusted to s '.This is included in step 202 and determines H _PqS be＜M or 〉=M.If H _PqS＜M, in step 240, adjust s '=(w*s)/M, perhaps if H _PqS 〉=M, then adjust s '=w in step 230.Affected pixel correspondingly deepens in the master image, as described in the image 12 of Fig. 1.

If for L _Pq, s=w then determines H in step 204 _PqS be＜M or 〉=M after, respective pixel H _PqSaturation degree be adjusted to s '.If H _PqS 〉=M, then adjust s '=w* (s-M)/(w-M), perhaps if H in step 210 _PqS＜M, in step 220, adjust s '=0, affected pixel correspondingly shoals in the master image, as described in image 13.

These equatioies are derived from the needs that sub-image embedded in the master image not discernablely.In order to realize this point, the pixel corresponding to the sub-image black picture element in the master image must deepen, and the white pixel of not having a color pixel corresponding to sub-image in the master image must correspondingly shoal.This be the maximum possible degree finish when remaining on the total saturation degree of master image in the minimum Probability Area.

Fig. 3 and Fig. 3 B have described at sub-image L _PqThe pixelation partial L of middle supposition _{P ' q '}310.Sum of all pixels in this zone is w.In such zone, all pixels all are restricted to maximum (s=0) or minimum (colourless; S=w) saturation degree.The sum of all pixels w that occurs is therefore corresponding to weight (saturation degree) quantity that can use the regional maximum possible of reproducing of such pixelation.In Fig. 3 B, certain number of pixels is set as maximum saturation 370, and other has minimum saturated 330.For convenience's sake, the maximum saturation pixel is separated from no color pixel and is combined into one group at the left-hand side of Fig. 3 B.Therefore, the absolute quantity M that the average staturation in pixelation zone will equal not have color pixel multiply by its saturation degree w, adds that the absolute quantity (w-M) of maximum saturation pixel multiply by its saturation degree 0, divided by sum of all pixels w (Fig. 3).

That is to say sub-image L _PqMiddle area L _{P ' q '}Average staturation be:

$s\left(L_{p^{\′}{q}^{\′}}\right)=\frac{0*(w-M)}{w}+\frac{w\left(M\right)}{w}=M...\left(1\right)$

For should zone and master image H _PqIn corresponding region H _{P ' q '}Be complementary, M must equal matrix H _{P ' q '}In master image average staturation s ' (H _{P ' q '}).

If s ' (H _{P ' q '}) value less than M, then should the zone darker in master image than in sub-image, must from this zone, remove intensity (saturation degree).That is to say that the maximum saturation pixel in this regional master image must be substituted by no color pixel.Therefore, must create the no color pixel of extra quantity.New saturation degree s ' is the following equation of substitution (1) effectively:

$s\left(L_{p^{\′}{q}^{\′}}\right)=\frac{0*(w-M)}{w}+\frac{s^{\′}\left(M\right)}{w}$

This equation of resetting obtains:

s′(H _p′q′)＝(w*s)/M ...(2)

Yet, if s ' (H _{P ' q '}) value greater than in M, then should the zone more shallow in master image than in sub-image, must add intensity (saturation degree) to this zone.That is to say that the no color pixel in this regional master image must be substituted by the maximum saturation pixel.New saturation degree s ' is the following equation of substitution (1) effectively:

$s\left(L_{p^{\′}{q}^{\′}}\right)=\frac{s^{\′*}(w-M)}{w}+\frac{w\left(M\right)}{w}$

This equation of resetting obtains:

s′＝(w*(s-M))/(w-M) ...(3)

In order this to be reduced to relatively sub-image L by pixel _PqIn each pixel can only have the saturation degree of s=0 (maximum saturation) or s=w (colourless).

Therefore, if s (L _Pq)=w and if s (H _Pq)＜M then is suitable for equation (2); Promptly

s′＝(w*s)/M

Yet if s 〉=M, s ' becomes more than or equal to w.S ' obviously is impossible greater than w, and therefore best s ' is set as:

s′＝w

Yet, if s (L _Pq)=0 and if s (H _Pq) 〉=M then is suitable for equation (3); Promptly

s′＝w*(s-M)/(w-M)

Yet, if s＜M, s ' vanishing or negative value.It is impossible that s ' becomes negative value, so s ' can be made as effectively and equal 0; Promptly

s′＝0

Therefore, the pixel intensity with the colourless corresponding master image of sub-image pixel reduces.And, increase with the pixel intensity of the corresponding master image of sub-image pixel of maximum saturation.This all is by keeping pixel even average staturation minimal set is finished near the mode of its previous mean value as far as possible.

Therefore, the application of this algorithm has constituted the form of shake, thereby wherein intensity is redistributed in minimum Probability Area sub-image is embedded in the master image.

Get back to Fig. 1 now; The modification part 14 of the master image with dominant hue cyan that produces by the cyan separating part 6 of substitution master image, produces the cyan separating part 9 of revision.The cyan separating part 9 of revision is reduced to monochrome image 10.

Each other separating part 3,4,5 whole process repeated to master image.Then, the separating part of revision is reconfigured and is produced securitized image.

Example 2 (colored sub-image is in colored master image):

With reference to Fig. 4: master image 400 is made up of colour picture.Use the known method of prior art, master image is separated 410 be its formation color-separated part; In this case, cyan (HC) 421, magenta (HM) 422, yellow (HY) 423 and black (HK) 424 separating parts are arranged.

Similarly, sub-image 430 is separated into its cyan (LC) 431, magenta (LM) 432, yellow (LY) 433 and black (LK) 434 separating parts.These separating parts can be used as " original " separating part of the final image of creating safe.Optionally, these separating parts can be further processed, and make it can be used as " original " separating part of the final image of creating safe.

Fig. 5 shows the example flow chart of the further processing of the sub-image separating part among Fig. 4; In this case, further handle to comprise and prepare color-separated and partly be used in conjunction with color phasegram.Among cyan (LC), magenta (LM), yellow (LY) and black (LK) the separating part 431-434 each is reduced to the gray level image that comprises predetermined weight (N) 501-504 quantity.Then use previous described method, each separating part is converted to PhaseGram511-514.Use previous described method, the strength range of the PhaseGram of the separation of generation is adjusted to the strength range of the original separating part 521-524 of coupling.Now, the image of strength matching is converted back to its tone separately, provides cyan (PCc), magenta (PMc), yellow (PYc) and black (PKc) the separating part 531-534 of correction.These separating parts can be used to create final securitized image now.

Fig. 6 A-6D shows the exemplary program that the sub-image separating part of " original " is converted to the sub-image separating part of " revision ".Each original separating part is coupled with the saturation degree of its tone correspondence in the negative film of other separating parts.This color for the sub-image of correct balance in master image is necessary.The sub-image separating part that produces is then shaken, to produce the sub-image separating part that pixel wherein has " revision " of maximum or minimum saturation degree.

Therefore, in Fig. 6 A, original cyan separating part (PCc) 531 is coupled with the cyan component 611 of the negative film 602,603,604 of magenta 532, yellow 533 and black 534 separating parts.After required shake, the cyan separating part of " revision " of generation is PCa621.In Fig. 6 B, original magenta separating part (PMc) 532 is coupled with the cyan component 612 of the negative film 601,603,604 of cyan 531, yellow 533 and black 534 separating parts similarly.After required shake, the magenta separating part of " revision " of generation is PMa 622.

Fig. 6 C and 6D show this and how to extend to yellow and black separating part.Therefore, original yellow separating part (PYc) 533 is coupled with the yellow color component 613 of the negative film 601,602,604 of cyan 531, magenta 532 and black 534 separating parts.After required shake, the yellow separating part of " revision " of generation is PYa 623.Similarly, original black separating part (PKc) 534 is coupled with the black component 614 of the negative film 602,603,604 of cyan 531, magenta 532 and yellow 533 separating parts.After required shake, the black separating part of " revision " of generation is PKa 624.

Fig. 7 A to Fig. 7 D show master image how by with the comparison of corresponding revision sub-image separating part, be converted into final securitized image.Therefore, main cyan separating part (HC) 421 pursues pixel relatively with the sub-image cyan separating part (PCa) 621 of revision.Use the algorithm 700 described in the example 1, thereby produce the cyan separating part (CC) 711 of final securitized image.Similarly, main magenta separating part (HM) 422 pursues pixel relatively with the sub-image magenta separating part (PMa) 622 of revision.Use the algorithm 700 described in the example 1, thereby produce the magenta separating part (CM) 712 of final securitized image.

Main yellow separating part (HY) 423 also pursues pixel relatively with the yellow separating part 623 of the sub-image of revising (PYa).Use the algorithm 700 described in the example 1, thereby produce the yellow separating part (CY) 713 of final securitized image.Similarly, main black separating part (HK) 424 pursues pixel relatively with the sub-image black separating part (PKa) 624 of revision.Use the algorithm 700 described in the example 1, thereby produce the black separating part (CK) of final securitized image.

Use the known appropriate method of prior art, separating part CC, CM, CY and CK are made up, create final securitized image.

Other embodiment

Above-mentioned algorithm provides the widest general contrasting region and to the best concealment of most of modulation digital images, yet other algorithms may be more suitable for specific application.And other algorithms may be more suitable for other hidden methods.Therefore, one skilled in the art will recognize that and to make multiple variation to aforesaid embodiments of the invention.It should be clearly understood that all such variations all comprise within the scope of the invention.

In addition, the present invention can have other performances.For example, prior art is known, and the color space or the separating part of tone and corresponding complementary tone thereof can be used to selectivity embodiment.

One skilled in the art will recognize that and to use other sub-image technology.For example, " scrambling mark (Scrambled Indicia) " at United States Patent (USP) 3,937, describes with analog in form in 565, in patent WO 97/20298 with the formal description of computerize, digital version.In the latter's technology, computer program cuts the image that will be called by implying in " input picture sheet " parallel rectangular effectively.Then they are produced a series of thinner " output map photos " by scrambling, and " output map photo " be it seems that with human eye disorderly form is incorporated in the image.Yet when checking by the specific installation that comprises many micro-tiny lens, original image is rebuilt, thereby presents visible hidden image.

This scrambling image can be incorporated in the visible background picture by the gray scale of hidden image or color saturation and background picture are mated.This is to realize by the thickness of adjusting the feature in the scrambling image.

Sub-image also can by " modulation " be used for the line of printing image-or dot pattern form.For printing image, the printer of specialty uses the technology of various being called as " screen ".Comprising round screen, random screen, line screen and oval screen.The example of such screen is seen United States Patent (USP) 6,104,812.In fact, picture is split into a series of images element, and typically, pictorial element is point or the line and the combination thereof of different shape.These Points And lines are minimum usually, can be observed much smaller than human eye.Therefore, the image that uses such screen to print has continuous color harmony concentration at human eye.

Hidden image can be by seeming similar line and some screen each other and put and create with two.The position, shape or the direction that are used to print the line element of screen by change come the processing procedure of hidden image formally to be called " line modulation ".The processing procedure that the point of printer screen is deformed or moves with sub-image is called as " some modulation ".The theory of line and some modulation is described (Issac Amidror, " The Theory of the Moir é Phenomenon ", KluwerAcademic Publishers, Dordrecht, 2000, pages 185-187) by Amidror.When two local period structures with same period superposeed each other, the image of generation had shown that two periodic structures the microstructure in zone of the differential seat angle of α=0 ° may be changed (and not the Moir é pattern of generation rule).The degree of the change of microstructure can be used to produce sub-image, and this sub-image is only just high-visible to the observer when local periodic structure is correlated with stack.Therefore, only when being applied non-modulation structure with correspondence, sub-image just can be observed.Correspondingly, modulation image can be incorporated into original document and corresponding to the decoding screen of non-modulation structure, the decoding screen be used for by for example on modulation image overlapping non-modulation decoding screen check to present sub-image whether document is original.

The example of using the line modulation to hide sub-image is described in following a plurality of patent: US6,104,812, US 5,374,976, CA 1,066, and 109, CA 1,172,282, WO03/013870-A2, US 4,143,967, WO 91/11331 and WO2004/110773 A1.A kind of technology or its microcosmic peer to peer technology " μ-SAM " that is called as screen angle modulation " SAM " is described in detail in U.S. Patent number 5,374,976 and Sybrand Spannenberg book " Optical Document Security; Second Edition " (editor: Rudolph L.vanRenesse, Artech House, London, 1998, page169-199) the 8th chapter in all is incorporated herein by reference.In present technique, in the pattern of the micro short line segment that is provided with in the cycle, by with continuously or the mode of blocking modulate micro short line segment angle relative to each other and create sub-image.When checking with naked eyes, pattern show as uniform in the middle of color or gray scale, when it superimposed with the identical non-modulation pattern on the transparent substrates on the time, can observe sub-image.

The example of using the some modulation to hide sub-image is described in the various patents, comprises WO02/23481-A1.

Further security strengthens and can comprise and use the fabricator's operable colored ink just that has only genuine notes ticket or other security document, and fluorescent ink or embed grid or the shape of forming pattern in image.

The method of the above embodiment of the present invention can be used to make safety equipment, thereby is strengthening security aspect the anti-counterfeit capability of bill, passport, license, currency and mail medium and so on article.Other useful applications can comprise credit card, photo I.D., bill, negotiable instrument, cashier's check, traveller's check, the label of clothes, medicine, drinks, video video tape or analog, birth certificate, vehicle registration card, land contract proof and visa.

Typically, safety equipment are by embedding securitized image and provide the decoding screen to provide individually in a kind of aforementioned document or certificate.Whether yet securitized image can realize at an end of banknote, and realizes the decoding screen at the other end, forge to allow verifying banknote.

Optionally, preferred embodiment can be used for the manufacturing as the new article of toy or encoding device and so on.

Claims (29)

1. method that forms securitized image comprises:

A) obtain the visible master image of observer;

B) acquisition will be hidden the sub-image into master image;

C) adjust the saturation degree in the zone of at least one in master image and the sub-image, make that the saturation degree of combination zone more approaches the saturation degree of the corresponding region of original master image when adjusted sub-image and master image make up subsequently; And

D) sub-image and adjusted master image are made up, to form securitized image.

2. the method for claim 1 comprises the adjustment saturation degree, so that minimize the difference of the saturation degree of the saturation degree of the image that is combined into by adjusted sub-image and master image and original master image.

3. the saturation degree of the method for claim 1, wherein adjusting the zone at least one master image and the sub-image comprises:

Each of master image and sub-image is separated into the digitizing gray scale of each image of complete definition when making up or the set of color saturation;

Each gray scale or color saturation are used matching algorithm, the gray scale of the pictorial element in the sub-image or the same grayscale of color character and master image or the correspondence image element of color saturation are mated.

4. the method for claim 1, wherein making up adjusted sub-image and master image comprises:

According to the visual properties of the selected pictorial element of sub-image, the selected correspondence image element of each gray scale or color saturation in the master image is changed, to form the separating part of revision; And

Thereby the separating part of combination revision is created securitized image.

5. as each described method in the claim 1 to 4, wherein, obtain sub-image and comprise: the sub-image of selecting one or more image and the formation that will hide into master image to comprise one or more images.

6. the method for claim 1 also comprises:

A) obtain another sub-image that to hide at least;

B) saturation degree in the zone of at least one in adjustment securitized image and another sub-image, make that the saturation degree of combination zone will more approach the saturation degree of the corresponding region of original securitized image when adjusted another sub-image and securitized image make up subsequently; And

C) adjusted another sub-image and securitized image are made up, form another securitized image.

7. as each described method in the claim 1 to 6, wherein, sub-image is the hidden image of coding, and the hidden image of described coding can use the decoding screen to decode.

8. method as claimed in claim 7 comprises that the technology by selecting forms sub-image from following group: scrambling mark, line or some modulation, PhaseGram and BinaGram.

9. method as claimed in claim 7, wherein, sub-image is the digital modulation image.

10. as claim 5 or 6 described methods, wherein, a plurality of sub-images are can be hidden into visible securitized image by the mode of different decoder decodes separately.

11. safety equipment, comprise securitized image, in described securitized image, sub-image is hidden in the master image by following method: the saturation degree of adjusting the zone of at least one in master image and the sub-image, make when adjusted sub-image and master image make up subsequently, the saturation degree of combination zone will more approach the saturation degree of the corresponding region of original master image, and adjusted sub-image and master image are combined to form securitized image.

12. safety equipment as claimed in claim 11, wherein, sub-image is the hidden image of coding, and the hidden image of described coding can use the decoding screen to decode.

13. safety equipment as claimed in claim 12, wherein, sub-image is the digital modulation image.

14. as claim 12 or 13 described safety equipment, wherein, a plurality of sub-images are can be hidden into visible securitized image by the mode of different decoder decodes separately.

15. computer program code makes computer-implemented a kind of method that forms securitized image when carrying out described computer program code by computing machine, described method comprises:

A) obtain the visible master image of observer;

B) acquisition will be hidden the sub-image into master image;

C) adjust the saturation degree in the zone of at least one in master image and the sub-image, make that the saturation degree of combination zone more approaches the saturation degree of the corresponding region of original master image when adjusted sub-image and master image make up subsequently; And

D) adjusted sub-image and master image are made up, to form securitized image.

16. computer program code as claimed in claim 15 is set to adjust saturation degree, so that minimize the difference of the saturation degree of the saturation degree of the image that is combined into by adjusted sub-image and master image and original master image.

17. computer program code as claimed in claim 16 is set to adjust in the following manner the saturation degree in the zone of at least one in master image and the sub-image:

Each of master image and sub-image is separated into the digitizing gray scale of each image of complete definition when making up or the set of color saturation;

To each gray scale or color saturation, use matching algorithm, the gray scale of the pictorial element in the sub-image or the same grayscale of color character and master image or the correspondence image element of color saturation are mated.

18. computer program code as claimed in claim 17 is set to make up in the following manner sub-image and adjusted master image:

According to the visual properties of the selected pictorial element of sub-image, the selected correspondence image element of each gray scale or color saturation in the master image is changed, to form the separating part of revision; And

Thereby the separating part of combination revision is created securitized image.

19. computer program code as claimed in claim 15 wherein, obtains master image thereby computer program code is set to allow the user to import master image.

20. computer program code as claimed in claim 15 wherein, obtains sub-image and comprises: the sub-image of selecting one or more image and the formation that will hide into master image to comprise one or more images.

21. computer program code as claimed in claim 20 is set to allow the user to select the one or more images that will imply.

22. computer program code as claimed in claim 15 is set to:

A) obtain another sub-image that to hide at least;

B) saturation degree in the zone of at least one in adjustment securitized image and another sub-image, make that the saturation degree of combination zone will more approach the saturation degree of the corresponding region of original securitized image when adjusted another sub-image and securitized image make up subsequently; And

C) adjusted another sub-image and securitized image are made up, form another securitized image.

23. as each described computer program code in the claim 15 to 19, sub-image is the hidden image of coding, the hidden image of described coding can use the decoding screen to decode.

24. computer program code as claimed in claim 17 is set to form sub-image by the technology of selecting from following group: scrambling mark, line or some modulation, PhaseGram and BinaGram.

25. computer program code as claimed in claim 23, wherein, sub-image is the digital modulation image.

26., be set to a plurality of sub-images can be hidden into visible securitized image by the mode of different decoder decodes separately as claim 20 or 22 described computer program codes.

27. a computing system that is used to produce securitized image comprises:

The image importation is set to obtain master image and the sub-image that will hide into master image; And

Image processing section is set to:

Adjust the saturation degree in the zone of at least one in master image and the sub-image, make that the saturation degree of combination zone more approaches the saturation degree of the corresponding region of original master image when adjusted sub-image and master image make up subsequently; And

Adjusted sub-image and master image are made up, to form securitized image.

28. computing system as claimed in claim 27, wherein, image processing section is set to:

By each of master image and sub-image being separated into the digitizing gray scale of each image of complete definition when making up or saturation degree is adjusted in the set of color saturation;

To each gray scale or color saturation, use matching algorithm, the gray scale of the pictorial element in the sub-image or the same grayscale of color character and master image or the correspondence image element of color saturation are mated.

29. computing system as claimed in claim 27, be set to make up adjusted sub-image and master image, according to the visual properties of the selected pictorial element of sub-image, the selected correspondence image element of each gray scale or color saturation in the master image is changed, to form the separating part of revision; And

Thereby the separating part of combination revision is created securitized image.

Images